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node_example.module

This is an example outlining how a module can be used to define a new
node type.

Our example node type will allow users to specify a "color" and a "quantity"
for their nodes; some kind of rudimentary inventory-tracking system, perhaps?
To store this extra information, we need an auxiliary database table.

File

developer/examples/node_example.module

View source

<?php/**
* @file
* This is an example outlining how a module can be used to define a new
* node type.
*
* Our example node type will allow users to specify a "color" and a "quantity"
* for their nodes; some kind of rudimentary inventory-tracking system, perhaps?
* To store this extra information, we need an auxiliary database table.
*
* Database definition:
* @code
* CREATE TABLE node_example (
* vid int(10) unsigned NOT NULL default '0',
* nid int(10) unsigned NOT NULL default '0',
* color varchar(255) NOT NULL default '',
* quantity int(10) unsigned NOT NULL default '0',
* PRIMARY KEY (vid, nid),
* KEY `node_example_nid` (nid)
* )
* @endcode
*//**
* Implementation of hook_help().
*
* Throughout Drupal, hook_help() is used to display help text at the top of
* pages. Some other parts of Drupal pages get explanatory text from these hooks
* as well. We use it here to provide a description of the module on the
* module administration page.
*/functionnode_example_help($section) {
switch ($section) {
case'admin/modules#description':
// This description is shown in the listing at admin/modules.returnt('An example module showing how to define a custom node type.');
case'node/add#node_example':
// This description shows up when users click "create content."returnt('This is an example node type with a few fields.');
}
}
/**
* Implementation of hook_node_info(). This function replaces hook_node_name()
* and hook_node_types() from 4.6.
*
* This is a required node hook. This function describes the nodes provided by
* this module. The name value provide a human readable name for the node while
* the base value tells Drupal how the module's functions map to hooks (i.e.
* if the base is node_example_foo then node_example_foo_insert will be called
* when inserting the node).
*/functionnode_example_node_info() {
returnarray(
'node_example' => array(
'name' => t('example node'),
'base' => 'node_example',
),
);
}
/**
* Implementation of hook_access().
*
* Node modules may implement node_access() to determine the operations
* users may perform on nodes. This example uses a very common access pattern.
*/functionnode_example_access($op, $node) {
global$user;
if ($op == 'create') {
// Only users with permission to do so may create this node type.returnuser_access('create example node');
}
// Users who create a node may edit or delete it later, assuming they have the
// necessary permissions.if ($op == 'update' || $op == 'delete') {
if (user_access('edit own example nodes') && $user->uid == $node->uid) {
returnTRUE;
}
}
}
/**
* Implementation of hook_perm().
*
* Since we are limiting the ability to create new nodes to certain users,
* we need to define what those permissions are here. We also define a permission
* to allow users to edit the nodes they created.
*/functionnode_example_perm() {
returnarray(
'create example node',
'edit own example nodes',
);
}
/**
* Implementation of hook_menu().
*
* In order for users to be able to add nodes of their own, we need to
* give them a link to the node composition form here.
*/functionnode_example_menu($may_cache) {
$items = array();
if ($may_cache) {
$items[] = array(
'path' => 'node/add/node_example',
'title' => t('example node'),
'access' => user_access('create example node'),
);
}
return$items;
}
/**
* Implementation of hook_form().
*
* Now it's time to describe the form for collecting the information
* specific to this node type. This hook requires us to return an array with
* a sub array containing information for each element in the form.
*/functionnode_example_form(&$node) {
// We need to define form elements for the node's title and body.$form['title'] = array(
'#type' => 'textfield',
'#title' => t('Title'),
'#required' => TRUE,
'#default_value' => $node->title,
'#weight' => -5,
);
// We want the body and filter elements to be adjacent. We could try doing
// this by setting their weights, but another module might add elements to the
// form with the same weights and end up between ours. By putting them into a
// sub-array together, we're able force them to be rendered together.$form['body_filter']['body'] = array(
'#type' => 'textarea',
'#title' => t('Body'),
'#default_value' => $node->body,
'#required' => FALSE,
);
$form['body_filter']['filter'] = filter_form($node->format);
// Now we define the form elements specific to our node type.$form['color'] = array(
'#type' => 'textfield',
'#title' => t('Color'),
'#default_value' => $node->color,
);
$form['quantity'] = array(
'#type' => 'textfield',
'#title' => t('Quantity'),
'#default_value' => $node->quantity,
'#size' => 10,
'#maxlength' => 10,
);
return$form;
}
/**
* Implementation of hook_validate().
*
* Our "quantity" field requires a number to be entered. This hook lets
* us ensure that the user entered an appropriate value before we try
* inserting anything into the database.
*
* Errors should be signaled with form_set_error().
*/functionnode_example_validate(&$node) {
if ($node->quantity) {
if (!is_numeric($node->quantity)) {
form_set_error('quantity', t('The quantity must be a number.'));
}
}
else {
// Let an empty field mean "zero."$node->quantity = 0;
}
}
/**
* Implementation of hook_insert().
*
* As a new node is being inserted into the database, we need to do our own
* database inserts.
*/functionnode_example_insert($node) {
db_query("INSERT INTO {node_example} (vid, nid, color, quantity) VALUES (%d, %d, '%s', %d)", $node->vid, $node->nid, $node->color, $node->quantity);
}
/**
* Implementation of hook_update().
*
* As an existing node is being updated in the database, we need to do our own
* database updates.
*/functionnode_example_update($node) {
// if this is a new node or we're adding a new revision,if ($node->revision) {
node_example_insert($node);
}
else {
db_query("UPDATE {node_example} SET color = '%s', quantity = %d WHERE vid = %d", $node->color, $node->quantity, $node->vid);
}
}
/**
* Implementation of hook_nodeapi().
*
* When a node revision is deleted, we need to remove the corresponding record
* from our table. The only way to handle revision deletion is by implementing
* hook_nodeapi().
*/functionnode_example_nodeapi(&$node, $op, $teaser, $page) {
switch ($op) {
case'delete revision':
// Notice that we're matching a single revision based on the node's vid.db_query('DELETE FROM {node_example} WHERE vid = %d', $node->vid);
break;
}
}
/**
* Implementation of hook_delete().
*
* When a node is deleted, we need to remove all related records from out table.
*/functionnode_example_delete($node) {
// Notice that we're matching all revision, by using the node's nid.db_query('DELETE FROM {node_example} WHERE nid = %d', $node->nid);
}
/**
* Implementation of hook_load().
*
* Now that we've defined how to manage the node data in the database, we
* need to tell Drupal how to get the node back out. This hook is called
* every time a node is loaded, and allows us to do some loading of our own.
*/functionnode_example_load($node) {
$additions = db_fetch_object(db_query('SELECT color, quantity FROM {node_example} WHERE vid = %d', $node->vid));
return$additions;
}
/**
* Implementation of hook_view().
*
* This is a typical implementation that simply runs the node text through
* the output filters.
*/functionnode_example_view(&$node, $teaser = FALSE, $page = FALSE) {
$node = node_prepare($node, $teaser);
$order_info = theme('node_example_order_info', $node);
$node->body .= $order_info;
$node->teaser .= $order_info;
}
/**
* A custom theme function.
*
* By using this function to format our node-specific information, themes
* can override this presentation if they wish. We also wrap the default
* presentation in a CSS class that is prefixed by the module name. This
* way, style sheets can modify the output without requiring theme code.
*/functiontheme_node_example_order_info($node) {
$output = '<div class="node_example_order_info">';
$output .= t('The order is for %quantity %color items.', array(
'%quantity' => check_plain($node->quantity),
'%color' => check_plain($node->color),
));
$output .= '</div>';
return$output;
}